A virtual tape storage system (also referred to as a virtual tape library) is used to emulate an actual tape storage system. Many virtual tape storage systems are implemented as disk-based systems that contain virtual tape devices (implemented with disk-based devices) for emulating physical tape devices of the actual tape storage system.
A tape storage system is typically used for performing backup of data contained in various systems, such as application servers. However, tape storage systems are typically relatively slow, such that if the amount of data that has to be backed up is very large, then performing backups to tape storage systems becomes impractical. The use of virtual tape storage systems, containing disk-based devices, allows backup operations to complete in shorter amounts of time, since disk-based devices have higher access speeds than tape-based devices.
However, use of virtual tape storage systems is associated with various issues. For example, physical tape devices in the actual tape storage system and virtual storage devices in the virtual tape storage system can become un-synchronized such that when a backup software application attempts to restore from a particular physical tape device, the backup application may get confused if the physical tape device does not match what the backup application expects to see.